/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:        arm_mat_scale_f32.c
*
* Description:	Multiplies a floating-point matrix by a scalar.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
*
* Version 0.0.5  2010/04/26
*    incorporated review comments and updated with latest CMSIS layer
*
* Version 0.0.3  2010/03/10
*    Initial version
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupMatrix
 */

/**
 * @defgroup MatrixScale Matrix Scale
 *
 * Multiplies a matrix by a scalar.  This is accomplished by multiplying each element in the
 * matrix by the scalar.  For example:
 * \image html MatrixScale.gif "Matrix Scaling of a 3 x 3 matrix"
 *
 * The function checks to make sure that the input and output matrices are of the same size.
 *
 * In the fixed-point Q15 and Q31 functions, <code>scale</code> is represented by
 * a fractional multiplication <code>scaleFract</code> and an arithmetic shift <code>shift</code>.
 * The shift allows the gain of the scaling operation to exceed 1.0.
 * The overall scale factor applied to the fixed-point data is
 * <pre>
 *     scale = scaleFract * 2^shift.
 * </pre>
 */

/**
 * @addtogroup MatrixScale
 * @{
 */

/**
 * @brief Floating-point matrix scaling.
 * @param[in]       *pSrc points to input matrix structure
 * @param[in]       scale scale factor to be applied
 * @param[out]      *pDst points to output matrix structure
 * @return     		The function returns either <code>ARM_MATH_SIZE_MISMATCH</code>
 * or <code>ARM_MATH_SUCCESS</code> based on the outcome of size checking.
 *
 */

arm_status arm_mat_scale_f32(
    const arm_matrix_instance_f32* pSrc,
    float32_t scale,
    arm_matrix_instance_f32* pDst)
{
	float32_t* pIn = pSrc->pData;                  /* input data matrix pointer */
	float32_t* pOut = pDst->pData;                 /* output data matrix pointer */
	uint32_t numSamples;                           /* total number of elements in the matrix */
	uint32_t blkCnt;                               /* loop counters */
	arm_status status;                             /* status of matrix scaling     */

#ifndef ARM_MATH_CM0

	float32_t in1, in2, in3, in4;                  /* temporary variables */
	float32_t out1, out2, out3, out4;              /* temporary variables */

#endif //      #ifndef ARM_MATH_CM0

#ifdef ARM_MATH_MATRIX_CHECK

	/* Check for matrix mismatch condition */
	if((pSrc->numRows != pDst->numRows) || (pSrc->numCols != pDst->numCols)) {
		/* Set status as ARM_MATH_SIZE_MISMATCH */
		status = ARM_MATH_SIZE_MISMATCH;
	} else
#endif /*    #ifdef ARM_MATH_MATRIX_CHECK    */
	{
		/* Total number of samples in the input matrix */
		numSamples = (uint32_t) pSrc->numRows * pSrc->numCols;

#ifndef ARM_MATH_CM0

		/* Run the below code for Cortex-M4 and Cortex-M3 */

		/* Loop Unrolling */
		blkCnt = numSamples >> 2;

		/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
		 ** a second loop below computes the remaining 1 to 3 samples. */
		while(blkCnt > 0u) {
			/* C(m,n) = A(m,n) * scale */
			/* Scaling and results are stored in the destination buffer. */
			in1 = pIn[0];
			in2 = pIn[1];
			in3 = pIn[2];
			in4 = pIn[3];

			out1 = in1 * scale;
			out2 = in2 * scale;
			out3 = in3 * scale;
			out4 = in4 * scale;


			pOut[0] = out1;
			pOut[1] = out2;
			pOut[2] = out3;
			pOut[3] = out4;

			/* update pointers to process next sampels */
			pIn += 4u;
			pOut += 4u;

			/* Decrement the numSamples loop counter */
			blkCnt--;
		}

		/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
		 ** No loop unrolling is used. */
		blkCnt = numSamples % 0x4u;

#else

		/* Run the below code for Cortex-M0 */

		/* Initialize blkCnt with number of samples */
		blkCnt = numSamples;

#endif /* #ifndef ARM_MATH_CM0 */

		while(blkCnt > 0u) {
			/* C(m,n) = A(m,n) * scale */
			/* The results are stored in the destination buffer. */
			*pOut++ = (*pIn++) * scale;

			/* Decrement the loop counter */
			blkCnt--;
		}

		/* Set status as ARM_MATH_SUCCESS */
		status = ARM_MATH_SUCCESS;
	}

	/* Return to application */
	return (status);
}

/**
 * @} end of MatrixScale group
 */
